Method for preparing polyoxyalkylene primary amines



United States Patent Ofifi ce 3,151,682 Patented Dec. 15, 1964 3,161,682 METHOD FOR PREPARING POLYOXYALKYLENE PRIMARY AMINES Sherman D. Lesesne, Georgetown, and Norman 3. Godfrey and Philip H. Moss, Austin, Tex., assignors to Jefferson Chemical Company, Inc, Houston, Tex., a corporation of Delaware No Drawing. Filed Apr. 28, 1960, Ser. No. 25,187 Claims. (Cl. 260-584) The present invention relates to basic polyether compositions and, in particular, to a method for their preparation. The subject compositions may also be described as primary amine derivatives of polyalkylene glycols.

The basic polyether compositions prepared by the pres out process comprise a large class of polymeric materials having molecular weights in the range from about 100 up to about 10,000 and above. These compositions may be represented by the formula:

NH Z(oxyalkylene) OH in which Z represents a divalent radical which is an alkylene radical having 2 to 6 carbon atoms, cycloalkylene radical having 4 to 6 carbon atoms and a dialkylene ether radical having 4 to 6 carbon atoms and x represents a number from 2 up to about 200. These materials are as detergents, as solvents and as intermediates in the preparation of surface active agents, emulsifiers and corrosion-inhibiting compositions.

A three-step method for preparing the above-noted compositions is the subject of a commonly assigned copending Speranza et aL application Serial No. 860,317,

filed December 18, 1959, and entitled Method for Preparing Basic Polyether Compositions" now US. Patent 3,110,732. This three-step method involves the reactions of an alkanolamine with a carbonyl compound to form a condensation product, such as a Schifi base, followed by the reaction of the so-formed condensation product with an alkylene oxide to form a condensation productalkylene oxide adduct and finally by hydrolysis of the adduct to give a basic polyether composition. An improved method for the formationof basic polyether compositions hasnow been discovered. This method is more efiicient and obviates the need for forming intermediate condensation products as is required by the method previously employed.

Inaccordanee with this invention, oxyalkylation is efiected bycatalytically reacting an alkanolamine, de-

fined hereinbelow, with an alkylene oxide or 1,2-epoxy compound. An alkaline reacting alkali metal material is employed as the catalyst and high yields of primary amines are realized when a relatively high proportion of the alkaline reacting ean is employed in relation to the amount of the alkanolamine feed.

Alkanolamines which can be employed as starting reactants for the preparation of basic polyether compositions are represented by the formula:

in which Z represents a divalent radical which is a straight chain or branched chain alkylcne radical having 2 to 6 .carbon atoms, a cycloalkylene radical having 4 to 6 carbon atoms or a dialkylene ether ridical having 4 to 6 carbon atoms. The dialkylene ether radicals may be represented by the formula:

in which each R represents a hydrocarbon radical having 2 to 3 carbon atoms. Specific alkanolarnines which may be employed include monoethanolamine, l-amino2-propanoL Z-amino-l-propanol, 3-amino-1-propanol, 1-(2- aminoethoxykthanol, l-amino-Z-butanol, 2amino-3- butanol, Z-amIno-Z-methylpropanol, S-amino pentanol, 3-amino-2, Z-dimetnyl propanol, 4-arninocyclohexanol and the like.

The above-noted alkanolamines are directly reacted with an alkylene or olefin oxide in this process. Alkylene oxides which may be employed are represented by the formula.

in which R represents hydrogen or a 'hydrocarbon radical having in the range of l to 2 carbon atoms? fA single where Z has the values noted above and M is an alkali 'metal' In general, the catalysts are thestrongly alkaline "reacting alkali metals and compounds of the alkali metals. Suitable catalysts sodium hydride,- sodium .amide, sodium hydroxide, sodium alkoxides, such as sodium methoxide and sodium ethoxide and the correspond- .ing and lithium' compounds. *Water and a1- cohol formed respectively when a hydroxide or 'alkoxide catalyst is used must be removed before theeondensation product and catalyst mixture issubiect to oxyalkylation.

iAnother important feature of this process is the proportion of the alkaline reacting material employed in proportion to the alkanolamine reactant. Experiments have'been conducted in which ethylene'oxide and an amino alcohol were reacted at 100 C.' in the presence .of varying proportions of sodium asthe alkaline reacting material. At a molar ratio of sodiumlto amino alcohol of 0.65 to 1, the yield of amine was 32%. In-

creasing the molar ratio of the, sodium to monoethanolamine to 1 to 1, resulted-in 'a-primary amine yield of 51%. At sodium to monoethanolamine ratios of 13 to 1, a yield of 75% wasobtained. The dilierences indicate the importance of the amount of the catalyst in this 'process. In general, alkaline reacting material to alkanolamine molar ratios in the range from 0.521 up to 1 about 2:1 may be efiectively employed with sharply increased yields being obtained vith in the range from 12110 about 1.5:1. a

Direct oxyalkylation of an alkanolamine by the instant process may be carried out'over a broad rang'e of temperamres. This is illustrated by the following ruins conducted at various temperatures in which an amino alcohol and ethylene oxide were reacted in the presence of sodium.

The molar ratio of sodium to amino alcohol was held at 1.5 .to 1 during these experiments.- "The firstrun, which was carried out in the manner described and at a temperature of 40- C.,resulted in the productiouof'4% of a primary amine. A second experiment" conducted at '65 0., resulted in a 58% yield of a primary amine. In

a run at C., the yield of primary amine was 77% and a run at C. resulted in a primary amine yield of 88%. This process may be eliectively conducted at temperatures in a range from about 50 C. to about 200 C., with surprisingly improved yields being obtained at temperatures in the range from 100 to about 150 C.

The instant reaction may be conducted at atmospheric pressure although it is desirable to employ moderate pressures to increase the rate of reaction between the alltylene oxide and the alkanolamine. Pressures ranging from Example I 12 grams of monoethanolamine (0.2 mol), 7.0 grams of sodium (0.3 mol), and 100 grams of diethylene glycol dimethyl ether (used as a solvent) were placed in an autoclave. The vessel was evacuated, flushed with nitrogen and stirred for four hours at 150 C. The gas pressure created in starting up was relmsed and 184 grams of ethylene oxide reacted with the monoethanolamine at 150 C. and 20 p.s.i.g. over a period of 2 hours.

The product was diluted with 250 ml. of water and hydrochloric acid added to being the pH down to 11.0. Water and solvent were removed by distillation followed by stripping at 165 C. under vacuum. Sodium chloride precipitated as a result of this treatment and this was removed by filtration.

The product was a cream colored solid that melted at 30 to 34 C. The primary amine analysis was 0.898 meg/g. which is equivalent to a yield of 88.2%. The molecular weight was 960 (theory 980).

Example l 12 grams of monoethanolamine (0.2 mol), 8.5 grams of sodium hydride (0.5 mol), and 25 grams of diethylene glycol dimethyl ether (as a solvent) were placed in a one liter-three neck flask in an atmosphere of nitrogen. The flask was equipped with a stirrer and a'Dry Ice reflux condenser. This mixture was stirred for 20 minutes at a temperature of 100 C. after which ethylene oxide was added at atmospheric pressure. The reaction was maintained between 90 C. and 105' C. while 180 liams of ethylene oxide was added over a period of 3 The product was diluted with 250 milliliters of water and the pH hydrochloric acid. Water and solvent were removed by followed bya stripping treatment at 1691). under a vacuum. Sodium chloride, precipitated by the foregoing treatment, was removed by filtration.

The product was-a cream colored amolecnlar weightof l040andameltingpcintof29 C. Analysis indicated that the yield of primary amine was 64%.

Example 111 Monoethanolamine and ethylene oxide were reacted at 100 C.and40p.s.i.g.inamannersimilar.tothat described in Example I above. Sodiumfwas employed intheproportionofZSgramsofsodiumriermolof monoethanolamine but no solvent was employed. A

51% yield of a amine basic polyether composition having a molecular weight of=1075 was obtained. Example IV Monoisopropanolamine and sodium hydride were admixed in diethylene glycol dimethyl ether, the sodium hydride being present in the proportion of 42 grams per mol of monoisopropanolamin mixtrnewasreacted with ethylene oxide at 100' Grand atmospheric pressure in the manner desuibed in Example I above. A 62% yield of a basic polyether composition a. molecular brought down to 11.0 by the addition of which comprises the steps of reacting an alkanolamine having the formula:

with a strongly alkaline member selected from the group consisting of the metals, hydrides, amides and hydroxides of sodium, potassium and lithium in the molar ratio of said strongly alkaline member to said alkanolamine in the range from about 0.5 :l to about 2:1, and removing any by-product water and by-product alcohol of the reaction to thereby provide a first reaction mixture containing an anhydrous alkali alkoxide, adding to said first reaction mixture from about 2 to about 200 mols per mol of said alkanolamine of an alkylene oxide havinglt'he formula:

under reaction conditions including a temperature within the range of about 50 to about 200 C. and a pressure within the range of 0 to about p.s.i.g. to form a second reaction mixture containing said basic polyether and recovering said basic polyether from said second reaction mixture, Z in the above formulae being a member selected from the group consisting of C to C divalent alkylene groups, C to C cycloalkylene groups and C to C dialkylene ether groups represented by the formula:

' --R'--OR' x being a number from 2 up to about 200, R being selected from the group consisting of hydrogen, methyl and ethyl and R being a. hydrocarbon group containing 2 to 3 carbon atoms.

-2. A method for preparing a basic polyether composition having the formula:

NIL-Z-(oxyalkyleneh-OH which comprises the steps of reacting an alkanolamine having the formula? a strongly alkaline member selected from the group under reaction conditions including a temperature within the range of about 100 to about C. and a pressure within the range of 0 to about 100 p.s.i.g. to form a second reaction mixture containing said basic polyether and recovering said basic polyether from said second reaction mixture, Z in the above formulae being a member selected from the group consisting of C to C divalent alkylene groups, C to C cycloalkylene groups and C to C dialkylene ether groups represented by the formula:

x being a number froiri 2 up to about 200, Rbeiug selected from the group consisting of hydrogen, methyl and ethyl and R being a hydrocarbon group containing 2 to 3 carbon atoms.

3. A method as in claim 2 wherein the alkanolamine is monoethanolamine.

5 6 4. A method as in claim 3 wherein the strongly a1ka- References Cited in The file of this patent line member is sodium and the alkylene oxide is ethylene UNITED STATES PATENTS oxlda- 2,674,619 Lundsted Apr. 6, 1954 5. A method as m 01am 3 wherem the strongly alka- 2,763,529 Albrecht et al Sept 18 1956 line member is sodium hydroxide and the alkylene oxide 5 2,323 235 L 1 Feb 11 95 is ethylene Oxide. 2,871,266 Riley Jan. 27, 1959 

1. A METHOD FOR PREPARING A BASIC POLYETHER HAVING THE FORMULA: 